A hybrid ANPC three-level inverter unit and inverter

Abstract

This invention discloses a hybrid ANPC three-level inverter unit, including a frame, terminal blocks fixed on the frame, a water-cooled inverter unit, an input filter unit, a supporting capacitor, and a sensor. The switching transistors in the low-frequency unit are Si devices, and the switching transistors in the high-frequency unit are SiC devices. An inverter is also disclosed. This invention, through the hybrid arrangement of Si and SiC devices, can ensure the performance of the three-level inverter unit, achieve low switching losses of the switching devices, and fully utilize the advantages of the two different types of devices. The small size of the heat sink and the low cost of the device, along with the modular design, have outstanding advantages such as high integration, high power density, and good maintainability.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment technology, and relates to inverters, and more particularly to a hybrid ANPC three-level inverter unit and inverter based on SiC / Si devices. Background Technology

[0002] Currently, converters used in AC drive systems mainly employ traditional silicon-based structures. Compared to three-level inverter circuits constructed with traditional silicon devices, SiC (Silicon Carbide) devices with wide bandgap offer advantages such as faster switching speeds and lower switching losses. Compared to three-level inverter circuits constructed entirely with silicon carbide devices, they offer advantages such as smaller heat dissipation components and lower costs.

[0003] The high-frequency unit of the inverter operates under high-frequency, low-voltage stress conditions, and low-voltage, high-speed SiC devices can be used to reduce switching losses. However, if all of them are replaced with higher-performance SiC devices, the cost of a single device will be too high, which will reduce its adoption rate. Summary of the Invention

[0004] One of the objectives of this invention is to overcome the shortcomings and deficiencies of the prior art and to design a hybrid ANPC three-level inverter unit based on SiC / Si devices.

[0005] The technical solution adopted by this invention to solve its technical problem is: a hybrid ANPC three-level inverter unit, including a frame, terminal blocks fixed to the frame base plate by bolts, a water-cooled inverter unit, an input filter unit, supporting capacitors, and sensors; the water-cooled inverter unit includes a water-cooled heat sink and a low-frequency unit, a high-frequency unit, a discharge resistor, and their control board fixed to the water-cooled heat sink by screws. Both the low-frequency unit and the high-frequency unit contain multiple power device switching transistors. The switching transistors in the low-frequency unit are Si devices, and the switching transistors in the high-frequency unit are wide-bandgap SiC devices; the input filter unit includes an EMI filter board one, an EMI filter board two, and a magnetic ring; the supporting capacitor includes capacitors C1 and C2 connected in series; the sensors include a voltage sensor and a current sensor. The terminal blocks and voltage sensors are fixed to the side plate of the frame by screws to increase the space utilization of the inverter height.

[0006] The hybrid ANPC three-level inverter unit includes three Si device groups in its low-frequency unit: the first Si device group consists of a first, second, third, and fourth switch connected in series; the second Si device group consists of a third, fourth, ninth, and tenth switch connected in series; and the third Si device group consists of a fifth, sixth, eleventh, and twelfth switch connected in series. The collectors and emitters of the four switches in each Si device group are connected sequentially. After being connected in series, the collectors of the first, third, and fifth switches are connected in parallel to the positive terminal of the output of capacitor C1. After being connected in series, the emitters of the eighth, tenth, and twelfth switches are connected in parallel to the negative terminal of the output of capacitor C2.

[0007] The hybrid ANPC three-level inverter unit includes three SiC device groups in its high-frequency unit: the first SiC device group consists of the thirteenth, fourteenth, fifteenth, and sixteenth switches connected in series and then in parallel; the second SiC device group consists of the seventeenth, eighteenth, nineteenth, and twentieth switches connected in series and then in parallel; and the third SiC device group consists of the twenty-first, twenty-second, twenty-third, and twenty-fourth switches connected in series and then in parallel. The thirteenth and fifteenth switches are connected in parallel and then connected to the common terminal of the first and second switches via a laminated busbar. The seventeenth and nineteenth switches are connected in parallel and then connected to the common terminal of the series connection of the third and fourth switches via a stacked busbar. The twenty-first and twenty-second switches are connected in parallel and then connected to the common terminal of the series connection of the fifth and sixth switches via a stacked busbar. The fourteenth and sixteenth switches are connected in parallel and then connected to the common terminal of the series connection of the seventh and eighth switches via a stacked busbar. The eighteenth and twentieth switches are connected in parallel and then connected to the common terminal of the series connection of the ninth and tenth switches via a stacked busbar. The twenty-third and twenty-fourth switches are connected in parallel and then connected to the common terminal of the series connection of the eleventh and twelfth switches via a stacked busbar.

[0008] The hybrid ANPC three-level inverter unit is described above. Each Si device is composed of an insulated gate bipolar transistor (IGBT) made of Si material, and each SiC device is composed of a metal-oxide-semiconductor field-effect transistor (MOSFET) made of SiC material. Each switching transistor has a fast recovery diode connected in anti-parallel inside.

[0009] The hybrid ANPC three-level inverter unit uses thermally conductive silicone grease to dissipate heat between its IGBT and MOSFET switches and the water-cooled heat sink.

[0010] The control board of the hybrid ANPC three-level inverter unit includes a sampling unit, a signal acquisition unit, and a signal processing unit.

[0011] The aforementioned hybrid ANPC three-level inverter unit has a frame constructed from galvanized bent steel side plates and a bottom plate assembled by riveting.

[0012] A second objective of this invention is to provide an inverter that includes the aforementioned hybrid ANPC three-level inverter unit.

[0013] The beneficial effects of this invention are as follows: By replacing the high-frequency, low-switching-loss SiC devices in a traditional three-level inverter circuit composed entirely of Si devices, the SiC switching transistors have low voltage levels and high switching frequencies, offering advantages of low cost and high efficiency. At the same time, the power unit composed of hybrid SiC and Si devices is integrated on the same water-cooled plate, and the capacitors, EMI filters, sensors, and control components are evenly arranged in the same metal frame through modular layout, thereby improving the overall switching frequency of the inverter, increasing electromagnetic compatibility, increasing module integration, achieving higher system efficiency, and reducing costs. Attached Figure Description

[0014] Figure 1 This is a topology diagram of the inverter unit of the present invention;

[0015] Figure 2 This is a top view of the inverter of the present invention;

[0016] Figure 3 This is a perspective view of the inverter of the present invention;

[0017] Figure 4 This is a perspective view of the water-cooled inverter unit of the inverter.

[0018] Figure 5 This is a perspective view of the inverter's supporting capacitors.

[0019] The labels for each figure are as follows: 1—Frame, 2—Low-frequency unit, 3—Control board, 4—High-frequency unit, 5—Terminal block, 6—Output copper busbar, 7—Voltage sensor, 8—Support capacitor, 9—EMI filter board two, 10—Magnetic ring, 11—Discharge resistor, 12—Water-cooled plate radiator, 13—EMI filter board one, 14—Current sensor, 15—DC bus positive copper busbar, 16—DC bus negative copper busbar. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] This invention discloses an application for Figure 1 The invention presents a hybrid ANPC three-level inverter unit topology based on silicon carbide and silicon (SiC&Si) devices to solve the problems of low switching frequency or high switching loss of traditional Si devices. The hybrid ANPC three-level inverter unit provided by the invention has a more compact structure, higher integration, convenient installation and maintenance, and high power density.

[0022] Reference Figures 2 to 5 As shown, the present invention includes a frame 1, a terminal block 5 fixed to the frame 1 by bolts, an output copper busbar 6, a supporting capacitor 8, a water-cooled inverter unit, an input filter unit, a sensor, and a discharge resistor 11, etc.; the water-cooled inverter unit includes a water-cooled plate heat sink 12, a low-frequency unit 2, a high-frequency unit 4, a switching transistor driver board, a discharge resistor 10 and its control board 3, the low-frequency unit 2 and the high-frequency unit 4 both contain multiple power device switching transistors, the switching transistors in the low-frequency unit 2 are all Si devices, and the switching transistors in the high-frequency unit 4 are all wide-bandgap SiC devices; the input filter unit includes an EMI filter board 13, an EMI filter... The inverter includes a wave plate 9 and a magnetic ring 10, as well as a positive copper busbar 15 and a negative copper busbar 16. The sensors include a voltage sensor 7 and a current sensor 14. The supporting capacitor 8 includes capacitors C1 and C2 connected in series and encapsulated in the same capacitor structure. Its input and output leads are arranged side by side, and the copper busbar leads are directly connected to the input filter unit and the Si device switching transistor, reducing excessive lead components and making the structure compact. The terminal block 5 and the voltage sensor 7 are fixed to the side plate of the frame 1 with screws to increase the space utilization of the inverter height. The frame 1 is assembled by riveting galvanized bent steel side plates and a bottom plate.

[0023] The low-frequency unit 2 includes three Si device groups: the first Si device group is composed of a first switch S1, a second switch S2, a third switch S7, and a fourth switch S8 connected in series; the second Si device group is composed of a third switch S3, a fourth switch S4, a ninth switch S9, and a tenth switch S10 connected in series; and the third Si device group is composed of a fifth switch S5, a sixth switch S6, an eleventh switch S11, and a twelfth switch S12 connected in series. The collectors and emitters of the four switches in each Si device group are connected in sequence. After being connected in series, the collectors of the first switch S1, the third switch S3, and the fifth switch S5 are connected in parallel to the positive terminal of the output of capacitor C1. After being connected in series, the emitters of the eighth switch S8, the tenth switch S10, and the twelfth switch S12 are connected in parallel to the negative terminal of the output of capacitor C2.

[0024] The high-frequency unit 4 includes three SiC device groups: the first SiC device group consists of the thirteenth switch S13, the fourteenth switch S14, the fifteenth switch S15, and the sixteenth switch S16 connected in series and then in parallel; the second SiC device group consists of the seventeenth switch S17, the eighteenth switch S18, the nineteenth switch S19, and the twentieth switch S20 connected in series and then in parallel; and the third SiC device group consists of the twenty-first switch S21, the twenty-second switch S22, the twenty-third switch S23, and the twenty-fourth switch S24 connected in series and then in parallel. The thirteenth switch S13 and the fifteenth switch S15 are connected in parallel and then connected to the common terminal of the series connection of the first switch S1 and the second switch S2 through a stacked busbar. The seventeenth switch S17... After being connected in parallel with the nineteenth switch S19, it is connected to the common terminal of the series connection of the third switch S3 and the fourth switch S4 through a stacked busbar. After being connected in parallel with the twenty-first switch S21 and the twenty-second switch S22, it is connected to the common terminal of the series connection of the fifth switch S5 and the sixth switch S6 through a stacked busbar. After being connected in parallel with the fourteenth switch S14 and the sixteenth switch S16, it is connected to the common terminal of the series connection of the seventh switch S7 and the eighth switch S8 through a stacked busbar. After being connected in parallel with the eighteenth switch S18 and the twentieth switch S20, it is connected to the common terminal of the series connection of the ninth switch S9 and the tenth switch S10 through a stacked busbar. After being connected in parallel with the twenty-third switch S23 and the twenty-fourth switch S24, it is connected to the common terminal of the series connection of the eleventh switch S11 and the twelfth switch S12 through a stacked busbar.

[0025] The aforementioned switching transistors S1 to S24 are fixedly mounted on the water-cooled heat sink 12 with screws. The mounting surface of the switching transistors is coated with thermally conductive silicone grease to dissipate heat from the water-cooled plate, thereby improving the vibration resistance, shock resistance and heat dissipation performance of the power devices.

[0026] Each Si device in this invention is composed of an insulated gate bipolar transistor (IGBT) made of Si material, and each SiC device is composed of a metal-oxide-semiconductor field-effect transistor (MOSFET) made of SiC material. A fast recovery diode is connected in anti-parallel inside each switching transistor. Thermal grease is used to dissipate heat between the IGBT and MOSFET switching transistors and the water-cooled heatsink 12.

[0027] The control board 3 of the present invention includes a sampling unit, other signal acquisition units and a signal processing unit; the sampling unit detects the voltage and current in the bus through the voltage sensor 7 and the current sensor 14 respectively, and the signal processing unit processes external input signals, voltage and temperature signals, etc.

[0028] The supporting capacitors C1 and C2 of the present invention are integrated into a single structure through an integrated design. Inside the capacitor, C1 and C2 are connected in series. The copper busbars led out from the supporting capacitors are respectively connected to the positive copper busbar 15 of the DC bus, the negative copper busbar 16 of the DC bus, and the collector and emitter of the SiIGBT device.

[0029] The input filtering unit of the present invention consists of an EMI filter board 13, a magnetic ring 10, and an EMI filter board 9, which are arranged sequentially on the DC bus copper bus. The positive and negative poles of the filter board are directly fixed to the positive and negative copper bus of the DC bus by screws. The magnetic ring 10 is a hollow rectangular ring design that passes through the positive and negative copper bus of the DC bus and is fixed to suppress high-frequency interference signals.

[0030] The voltage sensor 7 of the present invention is fixed on the side plate of the frame 1 and connected to the positive and negative input side of the supporting capacitor 8 through leads; the terminal block is installed on the other side plate of the frame through a guide rail for connecting external secondary cables and increasing the stability of the cable.

[0031] The three-level inverter unit of this invention can be composed of high-voltage, low-frequency switching devices (such as high-voltage IGBTs) and low-voltage, high-frequency switching devices (such as SiC MOSFETs), thereby resolving the contradiction of simultaneously meeting the requirements of device voltage withstand and switching frequency. At the same time, the modular design solves the problems of difficult inverter installation and maintenance, large size, low power density, and high manufacturing cost.

[0032] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some of the application examples. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A hybrid ANPC three-level inverter unit, characterized in that: The system includes a frame (1), terminal blocks (5) fixed on the frame (1), a water-cooled inverter unit, an input filter unit, a supporting capacitor (8), and a sensor. The water-cooled inverter unit includes a water-cooled plate heat sink (12) and a low-frequency unit (2), a high-frequency unit (4), a discharge resistor (10), and a control board (3) mounted on the water-cooled plate heat sink (12). Both the low-frequency unit (2) and the high-frequency unit (4) contain multiple power device switching transistors. The switching transistors in the low-frequency unit (2) are Si devices, and the switching transistors in the high-frequency unit (4) are SiC devices. The input filter unit includes an EM I filter board one (13), EMI filter board two (9) and magnetic ring (10); the supporting capacitor (8) includes capacitors C1 and C2 connected in series, packaged in the same capacitor structure, with its input and output leads arranged side by side, and the copper busbars of the copper busbars directly connected to the input filter unit and Si device switching tube, so as to reduce excessive lead components and make the structure compact; the sensor includes voltage sensor (7) and current sensor (14), the terminal block (5) and voltage sensor (7) are fixed on the side plate of frame (1) to increase the space utilization of the inverter height, and the frame (1) is made of galvanized bent steel side plate. The plate and the base plate are installed by riveting. The voltage sensor (7) is connected to the positive and negative input side of the supporting capacitor (8) through leads. The terminal block (5) is installed on the side plate of the other frame (1) through a guide rail for connecting external secondary cables to increase the stability of the cables. The low frequency unit (2) includes three Si device groups: the first Si device group is composed of the first switch (S1), the second switch (S2), the third switch (S7) and the fourth switch (S8) connected in series, and the second Si device group is composed of the third switch (S3), the fourth switch (S4) and the ninth switch (S9). The third Si device group is formed by connecting the fifth switch (S5), the sixth switch (S6), the eleventh switch (S11), and the twelfth switch (S12) in series. The collector and emitter of the switch in each Si device group are connected in sequence. The collectors of the first switch (S1), the third switch (S3), and the fifth switch (S5) are connected in parallel to the positive terminal of the output of capacitor C1. The emitters of the eighth switch (S8), the tenth switch (S10), and the twelfth switch (S12) are connected in parallel to the negative terminal of the output of capacitor C2.The high-frequency unit (4) includes three SiC device groups: the first SiC device group consists of the thirteenth switch (S13), the fourteenth switch (S14), the fifteenth switch (S15), and the sixteenth switch (S16) connected in series and then in parallel; the second SiC device group consists of the seventeenth switch (S17), the eighteenth switch (S18), the nineteenth switch (S19), and the twentieth switch (S20) connected in series and then in parallel; and the third SiC device group consists of the twenty-first switch (S21) connected in series and then in parallel. The system consists of the 22nd switch (S22), the 23rd switch (S23), and the 24th switch (S24). The 13th switch (S13) and the 15th switch (S15) are connected in parallel and then connected to the common terminal of the series connection of the 1st switch (S1) and the 2nd switch (S2) via a laminated busbar. The 17th switch (S17) and the 19th switch (S19) are connected in parallel and then connected to the common terminal of the series connection of the 3rd switch (S3) and the 4th switch (S4) via a laminated busbar. The 21st switch (S21) and the 22nd switch (S22) are also connected. After being connected in parallel, the fourteenth and sixteenth switches are connected to the common series terminal of the fifth switch (S5) and the sixth switch (S6) through a laminated busbar. After being connected in parallel, the fourteenth switch (S14) and the sixteenth switch (S16) are connected to the common series terminal of the seventh switch (S7) and the eighth switch (S8) through a laminated busbar. After being connected in parallel, the eighteenth switch (S18) and the twentieth switch (S20) are connected to the common series terminal of the ninth switch (S9) and the tenth switch (S10) through a laminated busbar. After being connected in parallel, the twenty-third switch (S23) and the twenty-fourth switch (S24) are connected in parallel. Then, it is connected to the common terminal of the eleventh switch (S11) and the twelfth switch (S12) through a stacked busbar; the Si device is composed of IGBTs, the SiC device is composed of MOSFETs, and a fast recovery diode is connected in anti-parallel inside each switch. Thermal grease is placed between the IGBT switch and the MOSFET switch and the water-cooled heat sink (12); the control board (3) includes a sampling unit, a signal acquisition unit and a signal processing unit; the frame (1) is assembled by riveting galvanized bent steel side plates and a bottom plate.

2. An inverter, characterized in that, Includes the hybrid ANPC three-level inverter unit as described in claim 1.

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